Lab Grown Diamond Clarity Grades: What SI1 and VS2 Actually Mean

Published: July 30, 2026 Reading Time: 9 min Part 18 of the Zalkari Moissanite and Lab Grown Diamond Series

VS2 and SI1 are the two clarity grades that deliver the best value for most lab grown diamond buyers in 2026. Both are eye-clean  no inclusions visible to the naked eye at normal viewing distance  and both carry meaningful price savings over the VVS and Flawless grades above them. The premium for FL through VVS clarity pays for an absence of inclusions visible only under 10x magnification, not an improvement visible in everyday ring wear.

Clarity is the most misunderstood of the 4Cs for most buyers because the grading language sounds like a quality hierarchy where higher always means better. In practice, clarity only matters up to the point where inclusions become visible to the naked eye in face-up position. Beyond that threshold, additional clarity grade improvements are invisible in wear and represent cost without corresponding visible benefit.

The Clarity Scale: What Each Grade Actually Means

GIA and IGI grade diamond clarity using a scale that runs from Flawless at the top to Included (I3) at the bottom. All lab grown diamonds receive the same clarity grading as natural diamonds, identical criteria, identical scale.

FL (Flawless): No inclusions or blemishes visible under 10x magnification by a skilled grader. The top grade. Commands a significant premium.

IF (Internally Flawless): No inclusions visible under 10x magnification. Only minor surface blemishes may be present. Very close to FL in appearance; slightly lower premium.

VVS1 and VVS2 (Very Very Slightly Included): Inclusions extremely difficult to see under 10x magnification, even for a skilled grader. VVS1 inclusions are harder to detect than VVS2. Both are effectively invisible under any ordinary viewing condition.

VS1 and VS2 (Very Slightly Included): Inclusions visible under 10x magnification but characterized as minor. VS1 inclusions are slightly smaller or better positioned than VS2. Both are eye-clean  not visible to the naked eye at normal viewing distance.

SI1 and SI2 (Slightly Included): SI1 inclusions are visible under 10x magnification and may require careful observation to see with the naked eye in some stones. Most SI1 diamonds are eye-clean. SI2 inclusions are more prominent under magnification and some SI2 stones show visible inclusions to the naked eye; this grade requires examining the specific stone rather than relying on the grade alone.

I1, I2, I3 (Included): Inclusions visible to the naked eye. I1 may be acceptable for some jewelry types where the stone is not prominently displayed. I2 and I3 have obvious inclusions that significantly affect appearance.

The Eye-Clean Threshold: Where Clarity Grade Actually Matters

The concept of eye-clean is the most practical framework for applying clarity grades to purchase decisions. A stone is eye-clean if its inclusions are not visible when the stone is viewed face-up from a normal viewing distance  approximately 10 to 12 inches, which is typical for looking at a ring on the hand.

FL through VS1: all eye-clean. No debate. The inclusions in these grades are visible only under 10x magnification, not to the naked eye in any ordinary setting.

VS2: eye-clean in the vast majority of stones. Occasionally a VS2 stone will have an inclusion that, while classified VS2 by the grader, sits in a position or is of a type that makes it more visible than typical VS2. Reviewing photographs of the specific stone and its inclusion plot (the diagram on the grading report) helps confirm eye-clean status.

SI1: eye-clean in most stones but not all. The grade covers a range where some SI1 stones are easily eye-clean and others have inclusions that a careful observer might detect. Reviewing the specific stone  through high-magnification photographs or in person  is important at SI1.

SI2: not reliably eye-clean. A meaningful portion of SI2 diamonds have inclusions visible to the naked eye. Always examine the specific stone before purchasing SI2 clarity.

I1 and below: not eye-clean. Inclusions visible in face-up position.

The Price Difference Between Clarity Grades

At 1 carat, G color, Excellent cut lab grown diamond in 2026:

FL clarity: $3,000 to $5,000 IF clarity: $2,800 to $4,500 VVS1 clarity: $2,200 to $3,500 VVS2 clarity: $1,900 to $3,000 VS1 clarity: $1,500 to $2,500 VS2 clarity: $1,200 to $2,000 SI1 clarity: $900 to $1,500 SI2 clarity: $700 to $1,200

The price step from FL to VS2 is dramatic  $1,800 to $3,000 for a difference that is visible only under a loupe, not in everyday wear. The price step from VS2 to SI1 is approximately $300 to $500 for a difference that in most stones is also not visible to the naked eye in everyday wear.

For most buyers, VS2 or SI1 at Excellent cut in G or H color represents the optimal specification  maximum visible quality within a realistic budget.

Types of Inclusions and Why Placement Matters

Not all inclusions at the same grade affect appearance equally. The grading report's clarity diagram  called an inclusion plot  maps the location, type, and approximate size of inclusions within the stone. Understanding what types of inclusions are present and where they sit helps refine the grade's real-world meaning.

Feathers: small fractures within the stone. If positioned at the girdle or pavilion edge, they can affect durability under impact as well as clarity. If positioned toward the center of the stone, they may be more visible but less structurally significant.

Crystals: mineral inclusions trapped within the diamond during growth. Depending on size and color, these can range from invisible to obvious. Dark crystal inclusions are more visible than white or colorless ones at the same grade.

Needles: small elongated crystal inclusions, usually white. Typically less visible than dark crystals of equivalent size.

Clouds: groups of very small inclusions that create a hazy area. Individually invisible, but in aggregate can affect light transmission if large or dense.

Graining: internal growth irregularities from the crystal formation process. More common in some lab grown diamonds, particularly HPHT stones. Usually not visible in face-up position.

For inclusions at VS2 and SI1 grades, the position matters significantly. An inclusion positioned under a crown facet  visible in the face-up view  is more apparent than the same inclusion positioned under a prong in the final setting, where it will be hidden. Reviewing the inclusion plot for a VS2 or SI1 stone before purchase is worth doing.

Clarity and Cut Shape Interaction

Clarity grade interacts with cut shape in ways that affect the practical eye-clean threshold.

Brilliant cuts  round, oval, cushion, pear, princess  are the most forgiving of clarity because their faceting pattern maximizes light return, and the dynamic visual effect of brilliance and fire makes inclusions harder to detect. SI1 is often eye-clean in round brilliant stones.

Step cuts  emerald and Asscher  are the least forgiving of clarity. The long parallel facets create a clear window into the stone where inclusions are more visible than in brilliant cuts. VS2 or better is typically recommended for emerald and Asscher cut lab grown diamonds to maintain an eye-clean appearance.

Mixed cuts  radiant, which combines brilliant and step elements  fall between the two extremes. VS2 or SI1 is typically appropriate.

Reading the Clarity Section of a Grading Report

A GIA or IGI grading report for a lab grown diamond includes a clarity grade, a verbal description of the characteristics used to determine the grade, and a clarity diagram (inclusion plot) showing the location and approximate type of inclusions.

The clarity grade is the summary. The diagram is the detail. When purchasing a VS2 or SI1 stone online, request photographs of the specific stone alongside the grading report, and use the inclusion plot to understand where inclusions are positioned in relation to the stone's facets and the planned setting position.

Some vendors provide video of specific stones under magnification  extremely useful for SI1 stones where the grade covers a range from clearly eye-clean to borderline visible. A video shows inclusions in context, in motion, in a way that the grading report alone cannot.

Our lab grown diamond collection includes certification documentation on every listing.

Frequently Asked Questions

What does VS2 clarity mean in a lab grown diamond? VS2 (Very Slightly Included, level 2) means inclusions are visible under 10x magnification but minor in size and placement. VS2 lab grown diamonds are eye-clean  inclusions and are not visible to the naked eye at normal viewing distance. VS2 is a popular value grade that delivers excellent clarity appearance without the premium of VVS or Flawless grades.

What does SI1 clarity mean in a lab grown diamond? SI1 (Slightly Included, level 1) means inclusions are visible under 10x magnification. Most SI1 lab grown diamonds are eye-clean, but the grade covers a range; some SI1 stones have inclusions that are harder to see than others. Examining the specific stone through high-magnification photos or the inclusion plot is advisable at SI1.

Is VS2 or SI1 better for a lab grown diamond? For buyers who want maximum value with eye-clean certainty: VS2 is the safer choice  eye-clean in nearly all stones at this grade. For buyers comfortable examining specific stones: SI1 offers meaningful additional savings and most SI1 stones are eye-clean. Both are excellent value grades.

Do clarity grades matter more in some cuts? Yes. Step cuts  emerald and Asscher  require higher clarity grades (VS2 or better) because their faceting makes inclusions more visible. Brilliant cuts  round, oval, cushion  are more forgiving of clarity, and SI1 is often eye-clean in these shapes.

Is it worth paying for Flawless clarity in a lab grown diamond? For most buyers, no. The premium for FL over VS2 is significant  $1,800 to $3,000 at 1 carat  for a difference visible only under 10x magnification. In everyday wear, an FL diamond and a VS2 diamond of the same cut and color look identical.

How do I know if an SI1 diamond is eye-clean before buying online? Request high-magnification photographs of the specific stone, not stock images. Use the inclusion plot on the grading report to identify where inclusions are positioned. Look for video of the stone in motion. If in doubt, purchase from a vendor with a strong return policy that allows you to verify eye-clean status in person before committing.

Shop Lab Grown Diamonds at Zalkari

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